Advanced Battery Pack for Kia Soul EV

SEOUL – Feb 24, 2014: The Kia Soul EV is equipped with an advanced
power pack featuring lithium-ion polymer battery cells supplied by SK
Innovation. The pack, which has a class-leading energy density of 200
Wh/kg, is the result of a three-year joint development program between Kia
Motors Corporation and SK Innovation in Korea.

Engineers from Kia have developed the outstanding power pack featuring
192 lithium-ion polimer battery cells in eight modules, delivering a total
power output of 27 kWh. The pack incorporates state-of-the-art thermal
control technology to maintain individual cells at optimum temperature and
structural design to enhance crash worthiness.

Nickel-rich NCM (nickel-cobalt-manganese) cathode material is used in
the mass production of the battery cells for Soul EV. Energy density, which
is dependent on cathode capabilities, is a core performance factor deciding
EV driving range. By exploiting the class-leading energy density of its
battery, the Soul EV offers a driving range of ‘around’ 200 km
on a single charge.

High performance electrolyte additive and anode materials were also
developed to meet various performance requirements (such as safety and
lifecycle), while maintaining high energy density.

In addition, a special safety & secure separator is used in the Kia Soul
EV’s battery cells. The separator determines the safety and the
charge/discharge speed of the battery. It has improved thermal resistance,
which helps to keep the cell secure from exposure to heat or fire by
preventing the shrinking of the separator if the temperature of the cell
increases beyond normal levels.

The electrolyte additive used in the Soul EV will prevent the
degradation of battery performance at both low and high temperatures,
expanding the temperature range of the battery usage and reducing the
fluctuation of the driving range according to the weather.

Cold weather is notoriously hostile for a battery and the Soul EV
features a battery heating system, which warms-up the battery while the car
is plugged into the grid, prior to use. This helps to maintain optimum
battery performance regardless of external temperature.

For maximum ‘active safety’ the battery module is fitted
with an overcharge protection device that cuts the high voltage circuit if
ever the battery cell swelling phenomenon should occur due to
overcharging.

Optimization of the raw materials used to create the cathode morphology
control and surface coating, the anode surface coating and electrolyte
additive, plus the excellent mechanical strength of the separator, ensure
class-best durability and safety of the cell.

Background to Batteries A lithium-ion battery is a
rechargeable battery which saves the electric power as chemical energy and
uses it when necessary. The lithium-ions move from cathode to anode during
charging and from anode to cathode during discharging. The electrolyte is
necessary as a medium for the transfer of the lithium-ions and the
separator is necessary to separate the anode and cathode electrically.

Generally the cathode consists of heavy oxides and can store less
electricity per weight than the anode which consists of light carbons. To
increase the energy density (energy to weight) of the battery pack it is
important to increase the quantity of the electricity stored by the
cathode, since the quantity of electricity should be balanced between the
cathode and anode.

Lithium-ion polymer battery is the common name for the battery type
which uses ‘pouch film’ as a packing material. The name
lithium-ion battery refers to the battery type which uses a metal can as a
packing material.

The advantages of a lithium-ion polymer battery (compared to normal
lithium-ion batteries) include: greater efficiency due to the simple cell
structure (fewer parts), lower costs, increased safety and reliability
(thanks to better thermal diffusion and internal pressure control), ease of
manufacture in a variety of capacities and shapes.